It is often desirable to administer to a mammalian subject an opioid analgesic combined with a non-opioid analgesic agent, for example, acetaminophen (APAP). Such combination formulations provide the advantage of additive analgesic effects with a lower dose of opioid, and hence a resulting lower incidence of side effects and the ability to treat a broader spectrum of pain or pain states due to different mechanisms of actions.
Such is the case for combinations of acetaminophen or aspirin with opioids, such as oxycodone (Percocet® and Percodan®, respectively), or hydrocodone (Vicodin® and Lortab®, respectively) or acetaminophen with codeine (Tylenol® with codeine). However, these currently marketed drug products deliver the combination drugs as an immediate release product. Accordingly, the drug product has to be administered quite frequently and at least every 4 to 6. Currently, extended-release oral dosage forms for delivery of the above active ingredients are only available for delivery of a single active pharmaceutical ingredient. For example, Tylenol® Extended Release for Arthritis provides a dosage of 650 milligrams acetaminophen to be administered every 8 hours. OxyContin® is formulated to provide controlled release of oxycodone hydrochloride via twice-daily administration.
When treating a mammalian subject suffering from or diagnosed with a chronic or acute pain state, it is highly desirable to maintain and achieve analgesia continuously. Immediate release formulations of the appropriate therapeutic agents require frequent and/or continuous dosing throughout the day (or night) for continuous pain relief. This is often inconvenient and difficult to maintain regularly dosing and frequently leads to poor patient compliance, potentially resulting in a dose being taken after pain breaks through again, causing unnecessary pain and suffering.
Hence, it would be desirable and beneficial to provide extended release delivery of a drug product that comprises both an opioid and a non-opioid analgesic such as acetaminophen. Such a dosage form would reduce the frequency of administration to a subject while sustaining plasma drug levels and analgesic effects throughout the day (or night). Such an extended release dosage form would eliminate the need to dose frequently to maintain analgesia, which is often inconvenient and difficult to maintain regularly, with the result that the next dose is taken after the pain breaks through again, causing unnecessary pain and suffering. Additionally, such a dosage form would increase patient compliance while minimizing adverse effects or events.
Gastric retentive dosage forms have demonstrated success in providing extended delivery of active ingredients. Drugs that are delivered from a gastric retained dosage form continuously bathe the stomach, duodenum and upper part of the small intestine for many hours. Release of the drug from the dosage form upstream of absorption sites provides extended and controlled exposure of the absorption sites to the released drug, thus increasing bioavailability. Acetaminophen demonstrates reduced bioavailability when administered rectally (about 35-50%) as compared to oral administration (about 60-70%). The increasingly dry environment of the colon is unfavorable for absorption. Accordingly, a gastric retentive extended release dosage form would provide several significant advantages as it would obviate the bioavailability reduction seen in the colon with non-gastric retentive extended release dosage forms.
Although gastric retentive dosage forms containing a drug dispersed in a swellable polymer matrix have been previously described, new challenges arise when formulating dosage forms that can provide the therapeutically effective delivery of a combination of drugs, which include, for example, acetaminophen and an opioid. Firstly, these two active agents have very different solubilities. Acetaminophen is a sparingly soluble drug in water, having a solubility of about 1-5 milligrams/milliliter (mg/ml) in water at 22° C. In contrast, opioids, which are formulated as acid salts in drug products, are highly soluble in water. For example, oxycodone HCl (100 to 167 (mg/ml), hydrocodone bitartrate (62.5 mg/ml), and codeine phosphate (400 to 435 mg/ml). Such disparities in solubility should be taken into account when formulating a dosage form that releases the two active agents at rates proportional to each other. Secondly, opioids are known to inhibit gastric motility. Such inhibition can negatively impact the erosion rate of a gastric retentive dosage form as needed for the desired drug release profile. Finally, acetaminophen is known to be difficult for the production of solid oral dosage forms. It can be particularly difficult to produce a tablet having acetaminophen because acetaminophen powder does not compress easily to form a stable tablet. Moreover, preparation of tablets having necessary dosage levels requires a relatively high weight percent of the drug. As a result, production of a useful tablet size allows only low amounts of excipients. This contributes to the difficulties involved in producing a tablet that relies on the use of a swellable polymer for extended release.
The present disclosure meets these challenges and needs, among others.